.\" $OpenBSD: X509_get_pubkey.3,v 1.7 2019/06/14 13:59:32 schwarze Exp $
.\" selective merge up to: OpenSSL 99d63d46 Oct 26 13:56:48 2016 -0400
.\"
.\" This file was written by Dr. Stephen Henson <steve@openssl.org>.
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.Dd $Mdocdate: June 14 2019 $
.Dt X509_GET_PUBKEY 3
.Os
.Sh NAME
.Nm X509_get_pubkey ,
.Nm X509_get0_pubkey ,
.Nm X509_set_pubkey ,
.Nm X509_get_X509_PUBKEY ,
.Nm X509_REQ_get_pubkey ,
.Nm X509_REQ_set_pubkey
.Nd get or set certificate or certificate request public key
.Sh SYNOPSIS
.In openssl/x509.h
.Ft EVP_PKEY *
.Fo X509_get_pubkey
.Fa "X509 *x"
.Fc
.Ft EVP_PKEY *
.Fo X509_get0_pubkey
.Fa "const X509 *x"
.Fc
.Ft int
.Fo X509_set_pubkey
.Fa "X509 *x"
.Fa "EVP_PKEY *pkey"
.Fc
.Ft X509_PUBKEY *
.Fo X509_get_X509_PUBKEY
.Fa "X509 *x"
.Fc
.Ft EVP_PKEY *
.Fo X509_REQ_get_pubkey
.Fa "X509_REQ *req"
.Fc
.Ft int
.Fo X509_REQ_set_pubkey
.Fa "X509_REQ *x"
.Fa "EVP_PKEY *pkey"
.Fc
.Sh DESCRIPTION
.Fn X509_get_pubkey
attempts to decode the public key for certificate
.Fa x .
If successful it returns the public key as an
.Vt EVP_PKEY
pointer with its reference count incremented: this means the returned
key must be freed up after use.
.Fn X509_get0_pubkey
is similar except that it does not increment the reference count
of the returned
.Vt EVP_PKEY ,
so it must not be freed up after use.
.Pp
.Fn X509_get_X509_PUBKEY
returns an internal pointer to the
.Vt X509_PUBKEY
structure which encodes the certificate of
.Fa x .
The returned value must not be freed up after use.
.Fn X509_get_X509_PUBKEY
is implemented as a macro.
.Pp
.Fn X509_set_pubkey
attempts to set the public key for certificate
.Fa x
to
.Fa pkey .
The key
.Fa pkey
should be freed up after use.
.Pp
.Fn X509_REQ_get_pubkey
and
.Fn X509_REQ_set_pubkey
are similar but operate on certificate request
.Fa req .
.Pp
The first time a public key is decoded, the
.Vt EVP_PKEY
structure is cached in the certificate or certificate request itself.
Subsequent calls return the cached structure with its reference count
incremented to improve performance.
.Sh RETURN VALUES
.Fn X509_get_pubkey ,
.Fn X509_get0_pubkey ,
.Fn X509_get_X509_PUBKEY ,
and
.Fn X509_REQ_get_pubkey
return a public key or
.Dv NULL
if an error occurred.
.Pp
.Fn X509_set_pubkey
and
.Fn X509_REQ_set_pubkey
return 1 for success or 0 for failure.
.Pp
In some cases of failure of
.Fn X509_get0_pubkey ,
.Fn X509_set_pubkey ,
.Fn X509_REQ_get_pubkey ,
and
.Fn X509_REQ_set_pubkey ,
the reason can be determined with
.Xr ERR_get_error 3 .
.Sh SEE ALSO
.Xr d2i_X509 3 ,
.Xr X509_CRL_get0_by_serial 3 ,
.Xr X509_NAME_add_entry_by_txt 3 ,
.Xr X509_NAME_ENTRY_get_object 3 ,
.Xr X509_NAME_get_index_by_NID 3 ,
.Xr X509_NAME_print_ex 3 ,
.Xr X509_new 3 ,
.Xr X509_PUBKEY_new 3 ,
.Xr X509_REQ_new 3 ,
.Xr X509_sign 3 ,
.Xr X509_verify_cert 3 ,
.Xr X509V3_get_d2i 3
.Sh HISTORY
.Fn X509_get_pubkey ,
.Fn X509_set_pubkey ,
.Fn X509_REQ_get_pubkey ,
and
.Fn X509_REQ_set_pubkey
first appeared in SSLeay 0.6.5.
.Fn X509_get_X509_PUBKEY
first appeared in SSLeay 0.8.0.
These functions have been available since
.Ox 2.4 .
.Pp
.Fn X509_get0_pubkey
first appeared in OpenSSL 1.1.0 and has been available since
.Ox 6.3 .
